Conventionally, monitoring sleep of a person is implemented by an electroencephalography (EEG) device. The EEG device is capable of recording, during a sleep episode of the person, EEG data of the person and identifying a non-rapid eye movement (NREM) period and a rapid eye movement (REM) period. Other characteristics regarding the sleep episode may be obtained by analyzing the EEG data.
Taiwanese Patent No. 1405559 discloses a handheld sleep assistant device that enables a user to record biophysiological information and provides assistance regarding sleep for the user.